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Dik Zak writes with word of a paper published in the journal Hormones and Behavior. A study found that women take greater care over their appearance when they are at peak levels of monthly fertility. The researchers took two photos of each of 30 women, one near ovulation and one at the other end of her cycle. They then showed the paired photos (with faces obscured) to a group of observers, who were asked to judge in which photo the women were trying to look more attractive. The observers chose the "high fertility" subject nearly 60% more of the time than would be expected by chance.

Like you uhh know you we are (most of us) are at the 100% fertility rate most of the time and uhhh we don't care about advertising it. I am not sure where i am going with this. Oh snap, i need to shave the 4 month old beard. Wonder where dad keeps his razor...

> Like you uhh know you we are (most of us) are at the 100% fertility rate most of the time and uhhh we don't care about advertising it. I am not sure where i am going with this. Oh snap, i need to shave the 4 month old beard. Wonder where dad keeps his razor...

Apparently, for at least four times during that interval, it's been in Mom's drawer.

The article and summary are in disagreement. Choosing to assume the article is more likely to be right, it is 60% right guesses vs expected 50% right guesses.

However, also omitted from the summary is 42 guessers guessing on the 30 dress-up-women in the study. That's 42x30 guesses, with a 60% correct guess rate overall. 60% with more than a thousand sample points is well within the usual scientific standard for statistically significant.

actually the two linked articles are in disagreement. the dailymail article says that they chose the more fertile one 60% of the time. the newscientist article says that they chose the more fertile one 60% more of the time than would be expected by random (same as what the summary says).

and if i had to choose between the two, i'd say the newscientist article is more likely to be worded correctly.

For sake of argument, assume that there is an objective way to measure who takes greater care of their appearance and that all 42 judges are experts at measuring that and never wrong. In that case, these results boil down to 18 out of 30 women taking better care of their appearances during one of their ovulation phases than during one of their non-ovulation phases. When you combine that with the possibility that some of the judges could be wrong (thus increasing the expected variance), it's even less significant - not more. I'm going to go with Scooter on this one.

The published analysis is more analogous to saying that each women has a score that measures how much more or less attractively they dress during ovulation. In the article's case the score is defined in terms of the percentage of observers who think that a women is more attractively dressed during ovulation, with scores ranging from 0% to 100%. The 42 observers are used to estimate that score for each women. The reported percentage of 59.5% is the mean of these scores, and is not a percentage of the 30 women.

The analysis asks whether this mean score is greater than 50%. Whether or not significance is achieved with 30 observations in this case depends on the distribution of these 30 scores, which is not given in the article. Using only the information about the mean (59.5%), using a t.test (the actual analysis was more sophisticated, and included covariates) we can easily constuct p-values ranging from 0.1404 (12 women score 0%, 18 score 100%) to 5.969e-12 (15 women score 55%, 15 women score 65%)

It is possible (but presumably unlikely) that more women actually looked worse to a majority of the observers during ovulation and still get a mean score of 65% (for example if 22 women scored 45% and 8 scored 100%).

30 is a low sample size, but would not be unusual in psychology studies. There are statistical tests you can perform to find out the minimum effect size to declare significance. I've seen studies with meaningful results in as few as 8 samples.

Nevertheless, this particular study had 1260 samples. 42 guessers * 30 guesses each. More than a thousand samples is plenty for significance.

8 people have a physical ailment. 4 people receive surgery, 4 don't. The 4 receivers live, the 4 non-receivers all die.You have the ailment. Surgery or no surgery for you?

2 people guess a million times. They each get the right answer 600,000 each. Do you still assume it's a random guess? You may not believe that their power generalizes, but you darn well better believe in their power.

No, the slashdot summary is quoting New Scientist, which is also refered to by the Daily Mall article. Sounds to me like Daily Mall may be misquoting New Scientist, but of course the full New Scientist article isn't available online.

Where the word 'more' came from, other than slashdot summary, I don't know.

It came from the New Scientist article which was linked from the summary at the end of the sentence: "The observers chose the "high fertility" subject nearly 60% more of the time than would be expected by chance, according to the NewScientist.com writeup."

So like I was saying, it isn't the slashdot summary, it's Daily Mall and New Scientist which are contradicting each other.

Thank goodness for the real study, though, which makes it clear that it is New Scientist which is incorrect.

Much more interesting is women's tendencies to forget to take birth control, and to have affairs during ovulation [socialpsychology.org].

[W]hen women have sexual affairs with someone other than the husband or boyfriend, the affair often occurs during ovulation, the woman and her partner typically use no birth control, and the partner chosen by the woman has some quality that the husband/boyfriend lacks (Baker & Bellis, 1993; Bellis & Baker, 1990).

Well, yes and no.. there are postfertilization protections as well, so just because one ovulates doesn't mean the birth control wasn't working, just not working 100% (which it doesn't claim to). Still, you're right that not taking the pill will likely cause ovulation, so it gets back to the correlation/causation debate. At any rate, the study indicated an increase in "forgetfulness" around the time of would-be ovulation, as compared to the placebos taken during menstruation.

Check the article again [dailymail.co.uk], "The judges chose the photo taken during the fertile phases 60 per cent of the time."

The judges picked the fertile phase photo 60% of the time, when random chance would suggest 50%. This is an 20% more than random chance would predict. Significant, but not quite as amazing as a 60% difference that the summary erroneously suggests.

60% increase in observations picked correctly.They showed pairs of pictures of 30 women to a group of observers. Suppose there were 25 people in the test group ("observers"). Each was shown all 30 pairs of pictures. That's 25*30=750 observations, each with an opportunity to pick the right one.

Chance would say they'd pick the high-fertility picture 50% of the time; 325 out of 750 observations. Instead they picked it 60% more often than that, i.e. 520 times. (=1.6 * 325). The fact that there were 520

To two different articles. The word "more" came from the second link, which was to New Scientist, which according to the helpful link provided by brian0918, is wrong. It was in fact a 60% rate of picking the picture of the ovulating woman. Anyway, that's where the confusion came from.

From just personal female experience, I'll say it's probably true anyway. All of the girls I know (including myself) tend to wear hoodies, sweat pants and jeans during their least fertile time. However, I don't think the findings were properly analyzed.

Instead it seems women subconsciously don their trendier clothes, more jewellery, plaster on make-up and flash more flesh when they are the most fertile moment in their monthly cycle.

I would make a very safe bet that it isn't a subconscious thing at all.

There's a reason other than "randomness" that your wife bothers you more at times. It's not just because she thinks that you need "a break from your work". Open your eyes, men! She wants something from you!

My wife and I figured this out ages ago. She's all over me during ovulation. Anyone who's married and paying attention should also be able to notice this. But then again, how many guys know their wife's monthly schedule? Hmm.

You bother her because you know you can't get any. And when you can't get any, you feel you must have it. Relax, this is normal.

If that were the case I'd be after her all the time. More like I bother her because she is all bloated and juicy and I can tell she won't get pregnant.

What we're talking about is the situation where SHE is actively trying to get you to hump her. Pay attention to the signals she's sending. e.g. Nicely dressed, tasty dinner, "cuddling time", etc. Women express themselves more em

This works both ways. When she's near the end of her cycle, I'm near the end of my rope! Of course, women in general tend care less about everything near the end of their cycle, not just personal grooming. Does the phrase "Oh, to hell with it all, where's the Haagen Das?" ring any bells?

I learned something very early with my wife: when she hits ovulation, she's less interested me when I'm clean-cut and smelling good and all that and more interested in me when I haven't shaved, have been working outside all day, and am wearing some pretty rough-looking clothes.

The theory is that she goes for rugged-looking me because it makes me look stronger and tougher and so I look like a better choice for reproduction. "Strong man make strong babies" or something like that.

Knowing when she ovulates means knowing which days I can skip shaving and don't have to clean up before giving her a kiss after doing yardwork.

No disrespect intended toward your wife, but maybe you notice this time of the month in a positive light because the time before and during her period she's less sexy. In other words, if you see it like a wave, maybe it's not that the crest is so high, but that the trough is so low.The women I've known tend toward grumpiness just before their period, and often during it. In my experience, people who don't feel nice on the inside tend not to show it on the outside. I tend to notice sweat pants more often

I can smell when my wife is ovulating. Not consciously, but I get a lot more horny at the right time -- she got pregnant at age 37 three weeks after we got married, because I could "smell" it and we humped three times in 24 hours.

The next time was almost as fast -- five weeks after she stopped nursing, pregnant again.

According to my wife I have a genetic defect which causes me to be more attracted to her when she is menstruating. This has obvious disadvantages in that she is both unlikely to get pregnant and unlikely to not kick my ass when fondled in that state. Good thing I don't want kids, or a genetic legacy.

I sure do. It is called a sense of humor. That was a humerous rhetorical device. Hard to believe you have never heard or read a purposeful comedic double negative before. Is english not your first language?

You'd better be careful saying things like this around here, some slashbot will crop up and tell you that for lots of people on this thing, it isn't their first language.

Frankly I think that if someone wants to participate in a discussion in a given language, they should do all they can to master it, which is why I haven't moved someplace tropical yet... I feel a responsibility to speak the local language. I only wish more people in the USA felt that way...

TFA is a regular newspaper citing a New Scientist article, whose author may have read the original paper or perhaps just the press release.All that gets reported is what is old news, as you point out. The original work is by Baker and Bellis, and dates back to the 80s. but isn't cited in this article. Baker and Bellis' work has been criticized as being poorly controlled and subject to sample bias.

This study has a stronger statistical basis, and that's news. But most of the actual articles won't talk about

Exactly. Desmond Morris' "The Human Animal" documentary series from the mid 90s went into great detail the evolution of sexual behaviour. Women are more likely to wear less clothing when ovulating and they're more likely to cheat on their primary partners. Conversely men' penis heads are shaped like plungers to suction competitive sperm out of the woman's vagina, men are more likely to have a larger sperm count when separated from their primary partner for periods of time OR if they think she hasn't been fa

The case study was to small, only 30 women with only 2 pictures, not only did we not collect data, but with the lack of numbers we creates a very large error of margin.

Example, flip a coin once, and you get heads, your test reveals 100% heads when flipping a coin. Flip it 10 times, you got heads 3 times, so according to this test when flipping a coin you have 30% chance to get heads. Now flip it 100 times. That number will be a lot closer to 50%.

Try 1000 women with 6 pictures each (3 in prime and 3 out of prime) then have 100 different people scoring each card.

All this test does is shows is hey maybe there is something, and let us do a real test.

In a way there is. It's hard to tell without knowing the numbers. We have both uncertainty in the classification (the 42) and the uncertainty in the actual behavior of menstruating women (the 30). With what we have been told, it's possible that the classifications were actually always quite consistent (80/20 or something), but the preference regarding "ovulating/not ovulating" in fact shifted depending on the set of pictures shown. If so, we're basically back to 30 coin tosses. We certainly don't have 1260

The summary says that the fertile pic was chosen 60% more often than expected by pure chance, however the article states it was simply chosen 60% of the time, and that it was "Well beyond random chance" which is quoted in the article that way as well. The author may have known that the term might not be appropriate to describe a 60%/40% split with 30 subjects and 42 judges.

But hey, keep refining and expanding the group and see if the rate stays steady or increases. Could be very interesting.

When I'm at "the other end of my cycle" aka, my period, I'm bleeding and bloated and cramping and my face is breaking out, and looking pretty is not exactly high on my list. When I'm not, looking pretty is much less of a hassle. So, not exactly rocket science here.

When I'm at "the other end of my cycle" aka, my period, I'm bleeding and bloated and cramping and my face is breaking out, and looking pretty is not exactly high on my list. When I'm not, looking pretty is much less of a hassle. So, not exactly rocket science here.

They did a similar study a while ago in a bar. They would ask female volunteers to give a saliva sample and have their picture taken. Then they calculated the area of the body that showed skin and found a correlation between "showing more skin" and ovulation. So it's likely more than just wanting to feel pretty, I mean you don't go in a bar if you feel "bloated and cramping". To me it looks like women are more horny why they are ovulating, which makes perfect sense if you think in terms of evolution.

They did a similar study a while ago in a bar. They would ask female volunteers to give a saliva sample and have their picture taken. Then they calculated the area of the body that showed skin and found a correlation between "showing more skin" and ovulation. So it's likely more than just wanting to feel pretty, I mean you don't go in a bar if you feel "bloated and cramping". To me it looks like women are more horny why they are ovulating, which makes perfect sense if you think in terms of evolution.

Right.. because women just stop living one week out of every 4. Or, oh wait, they could just go out when they feel like that and try to have fun - you know, since they're not sick (like you would be if you were feeling like that) and there's no damn reason not to. But, no, probably not feeling all that "frisky."

The issue of looking good isn't the whole thing though, and we already know it's related to the cycle so that's not new information. Women will also tend to pick lower-cut tops and higher-cut bottoms at that point in their cycle, it's not just about how THEY look, it affects what they choose to wear and such as well. It's an overall shift in mood, which admittedly shouldn't surprise anyone who actually knows any women.

When I'm at "the other end of my cycle" aka, my period, I'm bleeding and bloated and cramping and my face is breaking out, and looking pretty is not exactly high on my list. When I'm not, looking pretty is much less of a hassle. So, not exactly rocket science here.

But all the rocket scientists have real jobs so the scientists that were left over ended up working on this project;)

does it really mean anything for us humans? I mean, if women actually attracted more men when they look attractive, then we wouldn't have had a surge of babies 9 months after the northeast power blackout, quite the contrary.I'm sure human being still have a tendency to "display" their fertility, by looks or by scents, on some unconscious level, simply because we're just really clever monkeys, but I'm not certain humans are receptive to these signals anymore, and if they are, psychological and intelligent de

but experimentally i've verified that i'm more likely to end up in a bed with a cute girl than someone with unfortunate looks.

Actually your preferences in girls are entirely societal: I'm assuming you're a westerner who prefers slim, tall, magazine-cover-beautiful girls, but if you were an animal, you'd opt for a fat, squat, muscular-looking female who would be statistically more able to have your babies and care for them.

Also, i've noted that if she grabs my package, i stop caring about looks until after t

I'm sure human being still have a tendency to "display" their fertility, by looks or by scents, on some unconscious level, simply because we're just really clever monkeys, but I'm not certain humans are receptive to these signals anymore, and if they are, psychological and intelligent decision-making processes in the brain probably supercede animal instincts.

I'm pretty damned sure that humans are still receptive to these signals. Haven't you ever been in the presence of someone who you didn't find all t

Actually, one of the hazards of sex is that animal instincts often do override intelligent decision-making processes. That's why many college campuses try to make condoms as available as possible (through conveniently-located vending machines, mainly, though student health at my college would give them out for free): They know students are going to be having sex, and when you're in bed with someone, y

does it really mean anything for us humans? I mean, if women actually attracted more men when they look attractive, then we wouldn't have had a surge of babies 9 months after the northeast power blackout, quite the contrary.

If HUMAN FEMALES really wanted to advertise fertility they have their nose light up and breasts double in size.

It's called "plastic surgery" (at least for the breast size), and it's designed to advertise fertility at some unconscious level. As for the nose thing, only female clown performers do that to attract male clowns.

I am a statistician, and reading through the comments hear, am saddened that many readers claim that "statistical significance" could not have been achieved in this study because of a sample size of 30 women. First, that's only part of the random sample in this study, the other part is men sampled to judge the pictures.

Second of all, I have looked up the actual publication in "Hormones and Behavior", and the p-value associated with their main test is.01, which usually signifies statistical significance.

Ultimately, determining whether some difference in populations is due to chance depends on more than just sample size. It depends on how large of a difference you want to detect, and the variance of the measurements within a group. Of course, larger sample sizes help, but it ultimately depends on what you're studying, and the design of the experiment.

So while I definitely applaud being sceptical of all statistics, I urge you to look up the actual publications, read the methodology, and then decide if the results are something you believe. Kneejerk reactions to n = 30 don't really help anyone though.

I am a statistician, and reading through the comments hear, am saddened that many readers claim that "statistical significance" could not have been achieved in this study because of a sample size of 30 women.

I blame schooling for this. Not counting my actual statistics classes, whenever I was asked to criticize a paper I always got credit for complaining that the sample size was too small, even when I knew I was completely full of shit and even when the various measurements of significance were sitting right there in the paper.

All you've got is the lone statistics course fighting even the other professors at a University, who apparently apply the statistical significance tests by rote, but don't really "believe" in them (or understand them to any degree). It's not hard to guess which will "win".

Doc: Thank you for volunteering for our experiment
Subject: That's fine. What's it about?
Doc: We can't tell you. But could you tell me what part of your menstrual cycle you're in?
Subject: So it's about menstrual cycles?
Doc: No. We ask everyone that quaestion.
Subject: I believe you.

To put this matter to rest, here are some relevant paragraphs of article text (thank you, worldwide university subscription):

MethodProcedure: photographic stimuli

Thirty women from the UCLA campus (mean age = 21.07 years old; SD = 2.35; range 18-37) posed for two standing full-body digital photographs with their hands placed at their sides (Canon PowerShot S410, 4.0 Megapixels). Women identified themselves as African American (n = 1), Asian American (n = 10), Caucasian (n = 6), Hispanic/Latino (n = 7), and mixed race or "other" (n = 6). One photograph was taken on a high fertility day of the cycle (follicular phase) and one on a low fertility day of the cycle (luteal phase). Photographs were taken in the same location under standardized lighting conditions against a plain blue background. All women reported regular menstrual cycles (ranging between 26 and 35 days), were partnered (involved in a "committed romantic relationship" with a man), and none had used oral or other hormonal contraceptives within the last three months. Because previous studies have found stronger ovulatory effects in partnered than in non-partnered women (e.g., Havlicek et al., 2005 and Pillsworth et al., 2004), we limited our investigation to partnered women.

Session scheduling and luteinizing hormone (LH) testing were conducted using the procedures described in Gangestad et al. (2002). There were three sessions--an initial session for cycle history assessment and scheduling and subsequent high and low fertility sessions. After initial sessions, women were scheduled to return for the next possible session (low or high) given their current cycle day. Low fertility sessions were scheduled to occur 4-10 days prior to the estimated day of next menstrual onset. Actual menstrual onset was reported by 66.7% of women after their low fertility session; for the balance of participants, menstrual onset was estimated using cycle length and the last date of menstrual onset. On average, based on these information sources, low fertility sessions took place 5.87 days prior to menses (SD = 2.5; three women participated within 48 h of menstrual onset and possibly could have experienced premenstrual symptoms; therefore, days-to-menstrual-onset is included in the analyses presented below). High fertility sessions were scheduled to occur 15-17 days prior to the next estimated menstrual onset. Participants also reported to the laboratory to complete urine tests beginning two days prior to their high fertility session and continuing for three days after this session or until an LH surge was detected. Using an unmarked commercially available urinary stick ovulation test (Clearblue(TM)), all women were judged to have an LH surge between three days after and two days before their high fertility session. An LH surge typically proceeds ovulation by 24-48 h (Guermandi et al., 2001); thus, all women were likely to be near ovulation during their high fertility session. Within the fertile window of the cycle, conception risk increases as ovulation approaches (Wilcox et al., 1995). We therefore estimated days-to-ovulation (by adding two to days-to-LH surge; mean = 3.03, SD = 1.40) and included this estimate in the analyses reported below.

These 30 women were a subset of 58 originally recruited for the study. Women ineligible for inclusion in the study either showed no evidence of an LH surge (n = 4), were rescheduled for low fertility sessions (due to their own time constraints) on days falling outside of the range of the luteal phase days (n = 3), did not consent to having photos taken (n = 7), consented to having their photos taken but did not consent to having their photos judged by people other than the researchers (n = 7), or did not complete all sessions (n = 7). There were no significant differences in relationship satisfaction, sociosexuality (Simpson and Gangestad, 1991), age, or relationship length between women retained in the study and those who were ineligible.

that if women dress more attractive when they are most fertile, as well as the fact that fertility for women falls sharply after age 30, that women generally don't give a crap about their appearance past age 30?

Doesn't seem to make a lot of sense to me, since women seem to put on more makeup, as well as visit the plastic surgeon more often as they get older. The vanity of women seems to increase with age if you ask me.

A study found that women take greater care over their appearance when they are at peak levels of monthly fertility.

Interesting, but hardly surprising. It reminds me of a cool evolutionary-psychology speculation about why women get bitchy when their periods start. The start of a period indicates that her partner has failed to impregnate her, so in terms of natural selection, that is the time to seriously reconsider the relationship.

In any case, it is deeply alarming to see such mounting evidence that most of our "free choices" are impelled from below, from the parts of our brains that still believe we are living in the jungle.

Moderators, for the love of....don't just give high ratings to people who post technical-sounding gibberish!!

The parent post is spreading misinformation with regard to the link between libido and di-hydro-testosterone (you'll note that he got the abbreviation incorrect, and attached a spurious "5a" to the front, because he confused the name of the enzyme -- 5-alpha-reductase -- responsible for DHT formation with the chemical itself!)

I'm not going to claim that DHT isn't involved with male sex drive, but it's certainly not the "primary mechanism" behind male libido. One needs only refer to the volumes of studies done on the relationship between selective serotonin reuptake inhibior antidepressants ("SSRIs", e.g. Celexa, Prozac, Paxil) and libido suppression to see that the issue is more complicated than a single hormone imbalance.

What makes this really galling, however, is that the guy has the guts to criticize real scientific research before spouting this crap, and you folks take it as some sort of authority!

but not directly caused by ovulation itself. The underlying reason is progestogen.

Who said it was caused by the ovulation itself? The article was just saying that women tend to dress more attractively when they are fertile. Whether that is caused by the ovulation itself, by progesterone, or random firings of the synapses is something that we still don't know.
progesterone is used in the final stages of ovulation